Sample Size for Independent Case-control Studies

 

Menu location: Analysis_Sample Size_Independent Case-Control.

 

This function gives the minimum number of case subjects required to detect a real odds ratio or case exposure rate with power POWER and two sided type I error probability ALPHA. This sample size is also given as a continuity-corrected value intended for use with corrected chi-square and Fisher's exact tests (Schlesselman, 1982; Casagrande et al. 1978; Dupont, 1990).

 

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Practical issues

 

Technical validation

The estimated sample size n is calculated as:

- where α = alpha, β = 1 - power, ψ = odds ratio, nc is the continuity corrected sample size, m is the number of control subjects per case, and zp is the standard normal deviate for probability p. n is rounded up to the closest integer.

 

 

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